Method of manufacture of inner tubes for vehicle tires



H. WAGNER 2,134,591

METHOD OF MANUFACTURE OF INNER TUBES FOR VEHICLE TIRES Oct. 25, 1938.

Original Filed Jan. 6, 1936 2 Sheets-Sheet 1 I I I I I," I I I INVENTOR Hans Wagner BY ENG/W58 W ATTORNEYS FiT H. WAGNER Oct. 25, 1938.

METHOD OF MANUFACTURE OF INNER TUBES FOR VfiHICLE TIRES Original Filed Jan. 6, 1936 2 Sheets-sheaf, 2

INVENTOR Patented Oct. 25,1938

UNITED. STATES.

PATENT OFFICE.

METHOD OF MANUFACTURE -OF INNER t g TUBES FOB. VEHICLE TIRES Hans Wagner, Akron, Ohio, assignor of eight per cent to Joseph P. Murphy, Jr., Brooklyn, N. Y., and two per cent to, StephenE. Ryan, 7

Forest Hills, N. Y.

Application January 6, 1936, Serial No. 57,754 r Renewed January 2 9, 1938 7 Claims. (01. 154 -141 i This invention relatesto inner tubes for pneumatic tires andmore particularly to an improved] provide-a;machine forfthe manufacture of inner tubes which is inexpensive to operate, simple in construction, -andwwhich willproduce new and improvedinner tubes.

,Aiurther object of this invention is to provide a method for the manufacture of inner tubes in .whichtheglbase of a valve stem may be inserted between :laminae. of the tube before the tube is vulcanized, V V a In the accompanying drawings, which constitute a part'ofmy disclosure, I haveillustrated a preferred embodiment of a machine for carrying out my invention, inwhich 1 v Figure-1 is a front elevation of the device; ysFig. ,2 isaside elevation of the device;illustratin iby broken lines,.theiposition of the carriage in a withdrawn-position; -Fig. 3 is'an enlarged fragmentary view, in secjtion, showing the steamtight journal Fig. dis a fragmentary view, in section, of thef-ree end of the'cylindrical drum; I

1 Fig. 5; is a fragmentary vertical section on line 5 -5yof Fig. 2; i V

Fig. 6. is aplan view of the cylindrical drum coatedwith rubber and illustrating the manner of.

forming thetubeon a drum; Fig. isaviewlsimilar to that shown in Fig. 6, illustrating at'C the appearance of the rubber. after it'has been inflated and therolling process startedand at D the appearance of the same rubber just before it is completelylrolledroff the freeend of the cylindrical drum;

Fig. *S'isa fragmentary section of the free end ofthe cylindrical drum, showing the recessed pocket providedtoreceive the valve stem; and

, Fig; 9. is a fragmentary view, inv section; of a portion of the-inner tube, after it has been rolled off=lthefree end or the cylindrical-drum, illustrating;v the construction of the inner tube in the vicinity of the valve stem. 7 1 Y HBriefly, my method of manufacturing vehicle tire innerltubes consists of coating a cylindrical drum having a diameter of about the inside diameter of the finished tube with a rubber fi1m.,

At one end of the cylindrical drum a portion of this rubber. film or sheet is folded back upon itself,

the intermediate portion having first been coated with a substance to render the rubber film non; adhesive. Zinc stearate, for example, is satisfactory for this purpose. inserted through one thickness of this rubber film, and the portion of the film folded back upon itself is inflated to form a tubular or annular shell disposed circumferentially about the drum. This inflatedportion ofthe film is then rolled over the portion which remains about the cy-, lindrical, drum. It will beseen that, as the inflated portion rolls along the drum, it will gather up'the rubber filmin aplurality of concentric layers. Just before the end of the drum is reached a suitable valve stem having an en larged rubber base, isinserted through the initial layerof rubber film into a pocket in the drum.

providedf-for that purpose; The rubber filmis then'rolledoff the drum, carrying the base ofthe valve stem embeddedin it. A suitable hot im v plement may be inserted through the valve stem to suitably form an inflation opening through the concentric layers; of rubber, and effecting a com munication between the valve stem and :the interior of the tube. From this point the process-- ing of the tube is essentially the same as that now carried out in conventional inner tubemanufaeture; that is to say, it is placed in a suitable mold where itis inflated toa predetermined pres-, sure, and heat applied to vulcanize the rubber.

A more detailed description of thisiprocess and method may now be had by referringto the drawings.

The machine for carrying out my invention is providedwithape'destal 20. Securedin this pedestal is a supporting arm 2| upon which is mounted a'rotatable cylindrical 'drum 22. Beneath the aforesaid drum 22 and in an offset position is a which fitsa dip roller 26; The arrangement of this diproller, tank and carriage, supported by the aforesaid framework 23;}is such with respectto the drum 22 that, by suitable manipulationof a lever 21., the dip roller 26may be brought into contact'with the aforesaid drum 22. 1 The carriage 24 is'provided with axles 28 on'which are journaled suitable wheels 29 running on a suitable track formed by the flanges 39 of the angleirons 3} of the frame-23.

The frame :23 is so positioned with respect to the drum,22 that when'the carriage 24 is in the position illustrated by the full lines of Fig. 2, the dip roller 26 will be in contact with the drum 22. The carriage 24 may be moved upon the wheels An air needle is then 29 to the withdrawn position illustrated by the broken line of Fig. 2. Although any suitable means for performing this movement of the carriage 24 may be employed, I have selected the mechanism comprising the links 33 and 34, pivotally connected to the free end of thevbell crank arms 35 and 36 which are pivoted on the shaft 31 turning in journals 38. One end of the shaft,

39 affixed thereto 1 31 has a short crank arm which has its free end connected by the link 46 to a suitable point on the lever 21.

It will be seen that, by manipulation of the lever 21, the carriage 24 may be moved back and forth upon the frame 23, bringing the dip roller 26 into and out of contact with the drum 22.

It is desirable, for reasons to be hereinafter pointed out, to have the drum 22 heated and, although this may be done by any conventional method, I prefer to use steam. To make the drum steamtight one end of the drum is sealed by the head 4| and the other end of the drum is provided with a head 43 having a steamtight journal 42. The cylindrical drum 22 is supported on this journal by the head 43 which terminates in the bearing portion 44 rotatable on the supporting arm 2| and separated therefrom by the bearing metal'45. A portion of the member 42 is internally enlarged to accormnodate the steam packing 46 which is compressed by means of the collar 4! held in place by the machine bolts 48. At the free end 49 of the supporting arm 2| is mounted a spider 50 which has a rim portion 5| circumferentially in contact with the inner surface of the cylindrical-drum 22. The fixed end of the supporting arm 2| is held rigidly in the pedestal 26 by'means of the cap 52 and bolts 53. The supporting arm 2| is hollow. At the fixed end is a steam cap 54 into which is fitted a steamline pipe 55 having a-suitable valve 56. It will be seen that the steam for heating the drum mayenter the-hollow supporting arm 2| through the cap 54, and be introduced to the inside of the drum 22 throughone or more holes 57 in the supporting arm 2|. with its depending portion 58 will carry off the condensate and waste steam; The waste pipe 58 passes through the cap 59 at the free end of the supporting arm 2|, then through the entire drum 22 is desired, any suitable steam trap (not shown) may be inserted in. the pipe 58"to restrict the fiow of steam but permit the flow of water.

The hub 44 of the steamtight journal 42 has a sheave 60 that accommodates the belt 6| which runs in the sheave 62 of the gear box 63 andis operated by the motor 64.

Adjacent the free end of the drum 22 is a pocket or recessed portion 65 communicating with the surface of the drum and of a size adapted to receive a valve stem. A perforated spray pipe 61 is supported over the cylindrical drum 22 by a suitable support 66 which is secured to and movable with the carriage 24. The spray pipe 61 is connected by a suitable flexible conduit 68 to a source of acid (not shown) which is used for the purpose of coagulating the rubber latex as it is collected on the rotating cylindrical drum 22 as well known to those skilled in the art.

In order to prevent objectionable collection of foreign matter in the latex tank 25, I propose to substantially enclose this tank and theroller 26 by means of a hood 69. The'carriage 24 also or with a suitable rubber cement.

The waste pipe 58 carries a drip pan In, which is adapted to catch the excess acid, if any.

In employing the above described apparatus for the manufacture of inner tubes for pneumatic tire casings, the valve 56 is opened to admit steam to the drum 22 and the latex tank 25 is filled with rubber latex of a suitable composition When the temperature of the cylindrical drum 22 has been raised to the heat best adapted for working the particular latex or cement composition being handled, the motor 64 is turned on and, through the above mentioned gear box 63, sheaves 66 and 62, and belt 6|, the cylindrical drum 22 is rotated. By means of the lever 21 the carriage 24 is drawn across the framework 23 until the roller 26 is brought into peripheral contact with the cylindrical drum 22. As the friction between the drum 22 and roller 26 causes the latter to rotate, the valve H is opened and a spray of acid for coagulating the rubber latex is directed on the surface of the cylindrical drum 22. 26 rotates in the latex contained in the tank'25 its surface will become coated therewith and in turn transfer this latex to the surface of the cylindrical drum 22, it being a characteristic of the rubber latex to adhere to the warmer of two contacting rollers. This operation is continued until the latex on drum 22 is built up to a suitable thickness, approximately of an inch, at which time the valve fl is closed to shut off the supply of coagulating acid, and the lever 21 is operatedto withdraw the carriage 24 carrying the aforesaid latex tank 25, roller 26, drip pan l6, and acid spray pipe fi'lfrom the vicinity of the cylindrical drum 22. The rubber latex now forms a continuous, uniform, thin rubber film about the cylindrical drum. At the end of said drum near the steam tight journal 42 a portion 12 of this thin rubber, sheet is dusted with zinc stearate or soapstone and then folded back upon itself.

It may be desirable to trim the edges of the rubber sheet on the drum either to determine the length thereof, or to facilitate the carrying out of the method of inner tubeconstruction to be hereinafter described. This trimming may be accomplished in any suitable manner such as'cuttingit with a knife held against the rotating druml Referring to Fig. 6, the edge X-X of the sheet and the line 'Y--Y designate the boundaries of the area 12 of the rubber sheet to be coated with the nonadhesion agent. The lines X--X and Y-Y are separated a distance substantially equal to the internal circumference of theinner tube to be fabricated. The portion of therubber sheet adjacent the edge X-X is folded over the remaining treated portion 12 until the edge X--X substantially coincideswith the line Y'Y. A marginal portion of the edge X--X is then turned under as shown at 19 and the untreatedsurface of such margin pressed'against and united with the body portion of the sheet. It will now be observed that the folded over portion of the rubber,

tion of rubber fihn -jor sheet and' the-=circum-- ferentially disposed tube is inflated and itthen assumes the-shape indicated at Cof Fig. '7. In

this inflation process it will-"be seen that all 0fthe circumferentiallydisposed elements constituting this tube willbe more or less elongated except the elements lying adjacent the cylindrical drum22. When the tube has-been'inflated to the desired size, the air needle T3-is removed, the character of {the rubberifilm beingsuch that the hole made by the air needle is substantially sealed when the tube is wrapped on itself. In this infiatedposition ther'ubber tube circumferentially disposed about the drum 22 is rolled 1' upori'the thin rubber film or sheet towards the free end of drum 22; It will be observed that centric layers and', in cross'-section,-wou1d appear as at D of Fig. 7 to be progressively'compacted laminations. Just *before the tube reaches the free end 15 of the cylindrical drum 22 a valve stem 16 is inserted through the rubber. film or sheet, which is still circumferentially disposed about the drum 22, and extends into the pocket 65 carried by the drum. Because the recessed portion 65 of the drum 22 does not contact the dip roller 26, the elastic film is not formed over the pocket which opens to the surface of the drum. If the inflated rubber tube be now completely rolled off the free end 15 of thecylindrical drum 22, it will be seen thatjthe valve stem 16 is carried therewith and the enlarged base 11 of the said valve stem 16 is secured between the outer and the second outer layers of the rubber film constituting the tube. If a suitable heated probe 18 be now inserted through the valve stem 16, it will puncture the inner concentric layers of the rubber film constituting the tube and permit the inflation or deflation of the tubeby means of the valve stem 16. When the rubber tube is removed from the free end 15 of the drum 22 it is ready to be finally treated or cured by any conventional vulcanizing process.

If it is desired to produce a tube of larger size, it may be inflated internal stresses and of uniform construction.

The apparatusthat I have disclosed may be modified in many ways, and the process used in connection with it may be varied, within the spirit of my invention, to produce many different types of pneumatic tubes for tires. For example, if the length of the roller26 is adjusted so that a greater or lesser portion of the cylindrical drum 22 is coated with rubber latex from the tank 25,

inner tubes of different numbers of concentric layers of rubber may be constructed. By varying the width of the initial fold, the size of the tube can be regulated. Even if a large sized tube is desired, it sometimes may be advantageous to commence with a small sized tube and then. after it has been rolled off the freeend 15 of the drum 22, or at some intermediate point, it may be inflated to any desired size, as hereinabove mentioned. Regulating the amount of rubber latex or cement transferred from thetank 25 to the cylindrica'l drum22 by the rollers ZB'and the number of turns of the drum 22-controls the .Although a single embodiment of the invention has been herein shown and described-it will be understood that numerous modifications of the construction shown and of the method and process described may be resorted to without departing from the spirit of this invention as-defined in the appended claims. a

What I claim is:

l. The method of producing inner tubes for pneumatic tires which comprises forming an elastic sheet on a drum, folding an end portion of said sheet over an adjoining portion and uniting the marginal portion of saidend portion tothe sheet to form a closed annular tube circumferen tially disposed about said drum, inflating said tube, rolling said inflated tube over the remaining portion of the sheet, removing saidinflated tube from said drum, and curing the tube.

2. The method of producing pneumatic inner tubes comprising the steps of forming an elastic sheet on a drum, circumferentially trimming the edges of said sheet, folding one edge of said sheet over the adjacent body portion thereof and joining said edge circumferentially about said drum to said body portion of the sheet to form a flat tube circumferentiallydisposed about the drum, inflating the tube, rolling the inflated tube over the remaining portion of the sheet, and curing the tube, whereby a tube of homogeneous com-- position is formed,

3. The method of producing inner tubes for pneumatic tires comprising the steps of forming an elastic sheet on a drum, circumferentially trimming the edges of the sheet, coating a portion of the sheet adjacent the edge with a substance to render said portion non-adhesive, folding one edge of the sheet over the adjoining body portion of the sheet and turning under the marginal portion of the edge portion of the sheet and uniting the marginal edge portion of the sheet to an uncoated portion of the sheet adjacent said coated portion, thereby forming an annular tube circumferentiallydisposed about the drum, infiating the tube, rolling the inflated tube over the remaining portion of the sheet, removing the tube from the drum, and curing the tube.

4. The method of producing inner tubes for pneumatic tires which comprises forming an elastic sheet on a rotatable drum having one end free, trimming the edges of the sheet circumferentially around the drum, coating the portion of the sheet adjacent one end with a substance to render said portion of the sheet non-adhesive, folding over the end portion of the sheet and joining the said end portion circumferentially with-the centrally disposed uncoated portion of the sheet to form an annular tube circumferentially disposed about the drum, inflating the tube, inserting a valve stem through the sheet adjacent the free end of the drum with the base of the valve stem in engagement with the sheet, rolling the inflated tube over the remaining portion of the annular sheet which progressively adheres to and becomes a part of the annulus, removing the tube so formed from the drum and curing the same- 5. The method of producing inner tubes for pneumatic tires which comprises forming an elastic sheet on a drum having a free end, treating an end portion of said sheet with a substance to render said portion non-adhesive, folding said end portion of the sheet to form an annular flat tube circumferentially disposed about said drum, inflating said tube, and rolling said inflated tube over the remaining portion of said sheet and off the free end of said drum to form a plurality of compacted laminations about said inflated tube.

6. The method of producing inner tubes for pneumatic tires which comprises forming an elastic sheet on a drum, folding an end portion of said sheet over an adjoining portion to form a continuous flat tube ciroumferentially disposed about said drum, inflating said tube, inserting through said sheet at a position substantially removed from said circumferentially disposed tube a valve stem having an enlarged base portion in engagement with said sheet, stripping said inflated tube from said drum by rolling it over the remainder of the sheet and said valve base disposed thereon to form an inner tube of progressively compacted laminations with the valve base secured under the outer lamination, and curing said tube.

v '7. The method of producing inner tubes for pneumatic tires which comprises forming an elastic sheet on a drum, folding an end portion of said sheet over an adjoining portion to form a continuous flat tube circumferentially disposed about said drum, inflating said tube, inserting through said sheet at a position substantially removed from said circumferentially disposed tube a valve stem having an enlarged base portion in engagement with said sheet, stripping said inflated tube from said drum by rolling it over the remainder of the sheet and said valve base disposed thereon to form an inner tube of progressively compacted laminations with the valve base secured under the outer lamination, forming an inflation opening through the laminae of said inner tube beneath the valve stem, and curing said tube.

HANS WAGNER. 

